Hackathon - Task 1

Author:

Jasmin Mehnert, E-Mail: j.mehnert@students.hertie-school.org

Interactive map of US Senator birthplaces

# Install necessary packages if not already installed
required_packages <- c("sf", "dplyr", "tigris", "leaflet", "RColorBrewer", "legislatoR", "tidyr", "viridis")
new_packages <- required_packages[!(required_packages %in% installed.packages()[, "Package"])]
if(length(new_packages)) install.packages(new_packages)

# Load necessary librarys
library(sf)
library(dplyr)
library(tigris)
library(leaflet)
library(RColorBrewer)
library(legislatoR)
library(tidyr)
library(viridis)

# Data source acknowledgment:
# Göbel, Sascha and Simon Munzert. 2022. 
# "The Comparative Legislators Database". 
# British Journal of Political Science, 52(3), 1398-1408.

# Note: Assistance from ChatGPT was used to structure and debug this code.

# Extract data for USA Senate
usa_senate_core <- get_core(legislature = "usa_senate")

# Extract latitude and longitude out of birthplace columns
usa_senate_core <- usa_senate_core %>%
  filter(!is.na(birthplace)) %>% # delete NA values in birthplace
  separate(birthplace, into = c("lat", "lon"), sep = ",", convert = TRUE) %>% # Split in lat and lon
  mutate(lat = as.numeric(lat), lon = as.numeric(lon)) %>% # Convert to numerical
  filter(!is.na(lat) & !is.na(lon)) # Remove invalid coordinates

# Convert the senator data into sf-object
senator_points <- st_as_sf(usa_senate_core, coords = c("lon", "lat"), crs = 4326)

# Load shapefile of US-States
states <- tigris::states(cb = TRUE)

##   |                                                                              |                                                                      |   0%  |                                                                              |=                                                                     |   1%  |                                                                              |==                                                                    |   3%  |                                                                              |===                                                                   |   4%  |                                                                              |===                                                                   |   5%  |                                                                              |====                                                                  |   5%  |                                                                              |====                                                                  |   6%  |                                                                              |=====                                                                 |   6%  |                                                                              |=====                                                                 |   7%  |                                                                              |======                                                                |   9%  |                                                                              |=======                                                               |   9%  |                                                                              |=======                                                               |  10%  |                                                                              |========                                                              |  11%  |                                                                              |========                                                              |  12%  |                                                                              |=========                                                             |  12%  |                                                                              |=========                                                             |  13%  |                                                                              |==========                                                            |  14%  |                                                                              |==========                                                            |  15%  |                                                                              |===========                                                           |  15%  |                                                                              |===========                                                           |  16%  |                                                                              |============                                                          |  17%  |                                                                              |============                                                          |  18%  |                                                                              |=============                                                         |  18%  |                                                                              |=============                                                         |  19%  |                                                                              |==============                                                        |  20%  |                                                                              |==============                                                        |  21%  |                                                                              |===============                                                       |  22%  |                                                                              |================                                                      |  23%  |                                                                              |================                                                      |  24%  |                                                                              |=================                                                     |  24%  |                                                                              |=================                                                     |  25%  |                                                                              |==================                                                    |  25%  |                                                                              |==================                                                    |  26%  |                                                                              |===================                                                   |  27%  |                                                                              |==================================                                    |  48%  |                                                                              |==================================                                    |  49%  |                                                                              |===================================                                   |  50%  |                                                                              |===================================                                   |  51%  |                                                                              |====================================                                  |  51%  |                                                                              |====================================                                  |  52%  |                                                                              |=====================================                                 |  53%  |                                                                              |======================================                                |  54%  |                                                                              |======================================                                |  55%  |                                                                              |=======================================                               |  56%  |                                                                              |========================================                              |  56%  |                                                                              |========================================                              |  57%  |                                                                              |=========================================                             |  58%  |                                                                              |=========================================                             |  59%  |                                                                              |==========================================                            |  60%  |                                                                              |===========================================                           |  61%  |                                                                              |============================================                          |  62%  |                                                                              |============================================                          |  63%  |                                                                              |=============================================                         |  64%  |                                                                              |=============================================                         |  65%  |                                                                              |==============================================                        |  66%  |                                                                              |===============================================                       |  67%  |                                                                              |===============================================                       |  68%  |                                                                              |=================================================                     |  69%  |                                                                              |=================================================                     |  70%  |                                                                              |==================================================                    |  71%  |                                                                              |===================================================                   |  72%  |                                                                              |===================================================                   |  73%  |                                                                              |====================================================                  |  74%  |                                                                              |====================================================                  |  75%  |                                                                              |=====================================================                 |  76%  |                                                                              |======================================================                |  77%  |                                                                              |======================================================                |  78%  |                                                                              |=========================================================             |  81%  |                                                                              |=========================================================             |  82%  |                                                                              |==========================================================            |  83%  |                                                                              |===========================================================           |  84%  |                                                                              |===========================================================           |  85%  |                                                                              |============================================================          |  86%  |                                                                              |=============================================================         |  86%  |                                                                              |=============================================================         |  87%  |                                                                              |==============================================================        |  88%  |                                                                              |==============================================================        |  89%  |                                                                              |===============================================================       |  89%  |                                                                              |===============================================================       |  90%  |                                                                              |================================================================      |  91%  |                                                                              |================================================================      |  92%  |                                                                              |=================================================================     |  93%  |                                                                              |==================================================================    |  94%  |                                                                              |==================================================================    |  95%  |                                                                              |===================================================================   |  96%  |                                                                              |====================================================================  |  97%  |                                                                              |====================================================================  |  98%  |                                                                              |===================================================================== |  99%  |                                                                              |======================================================================|  99%  |                                                                              |======================================================================| 100%

# Transform states to WGS84, if needed 
if (st_crs(states) != st_crs(senator_points)) {
  states <- st_transform(states, st_crs(senator_points))
}

# Add US-State
senators_with_states <- st_join(senator_points, states, join = st_within)

# Delete NA-values (not born in USA)
senators_with_states <- senators_with_states %>%
  filter(!is.na(STUSPS)) %>%
  mutate(state = STUSPS)  # Add column with state

# Calculate number of senators per state
state_counts <- senators_with_states %>%
  group_by(state) %>%
  summarise(senator_count = n(), .groups = "drop") |>
  st_drop_geometry()

# Tabular join with left_join()
state_data <- states %>%
  left_join(state_counts, by = c("STUSPS" = "state")) %>%
  mutate(senator_count = replace_na(senator_count, 0))  # Fehlende Werte mit 0 auffüllen

# Use the viridis palette for colorblindness
color_palette <- colorBin(viridis(5, option = "viridis", direction = -1), 
                          domain = state_data$senator_count, bins = 5)

leaflet(data = state_data) %>%
  addProviderTiles(providers$OpenStreetMap.Mapnik) %>%
  setView(lng = -95, lat = 37, zoom = 3) %>%  # Fokus auf die USA
  addPolygons(
    fillColor = ~color_palette(senator_count),
    weight = 1,
    color = "white",
    fillOpacity = 0.7,
    popup = ~paste0(NAME, ": ", senator_count, " Senators"),  # Popup-Text anpassen
    label = ~paste0(NAME, ": ", senator_count, " Senators"),  # Tooltip-Text
    labelOptions = labelOptions(
      style = list("font-weight" = "bold"),
      textsize = "14px"
    )
  ) %>%
  addLegend(
    "bottomright",
    pal = color_palette,
    values = ~senator_count,
    title = "Number of Senators",
    opacity = 0.7
  ) %>%
  addControl(
    html = "<h2 style='color: black;'>Number of U.S. Senators Born in Each State</h2>",
    position = "topleft"
  ) %>%
  addControl(
    html = "<p style='color: grey; font-size:12px; text-align: left; 
          max-width: 300px; margin: 0;'>
          Data Source: Göbel, Sascha und Simon Munzert. 2022. 
          'The Comparative Legislators Database'. 
          British Journal of Political Science, 52(3), 1398-1408.
          </p>",
    position = "bottomleft"
  )